In the testing of wafer-based semiconductor devices, probe cards are typically used to provide electrical interconnection between a testing system and the semiconductor wafer. Such probe cards may, for example, include a Printed Circuit Board (PCB), a probe substrate and an interposer (e.g., a pogo pin or spring pin based interposer) that provides electrical interconnection between the PCB and the probe substrate. Resilient probe elements are supported by the probe substrate. For example, in certain probe cards, the probe elements may be held in a “floating” configuration within a probe head adjacent the probe substrate. In other probe cards, the probe elements may be fixed at one end to a conductive region (e.g., a conductive trace, a terminal, a lead, a contact pad, etc.) of the probe substrate.
The probe elements may have different configurations depending upon the testing application. For example, cantilever style probes are sometimes used in the testing of memory devices. Cantilever probes typically include beam element mounted to a post element located adjacent a conductive region on a probe substrate. The beam element is mounted to the post element at one end of the beam so that the other end of the beam is suspended in a cantilever configuration. The suspended end of the beam element includes a tip portion that is configured to probe a contact pad or other feature of the semiconductor device being tested.
Probe elements are conventionally attached to a probe substrate by, for example, epoxy bonding, solder reflowing, or TAB bonding. These conventional approaches have some limitations. For example, TAB bonding requires a gold intermediate layer between the probes and the probe substrate, or between the beam element and the post element for cantilever probes. The strength of a TAB bond is relatively weak, any repair or adjustment can lead to the detachment of probes from the substrate. Once the probes are detached, it is very difficult to TAB bond new probes in the same location because of the contamination and peeling of gold that remains from the original bond.